Combined arc lamp and incandescent lamp



y 9, 1939- H. .1. BRUNK 2,158,026

COMBINED ARC LAMP AND INCANDESCENT LAMP Original Filed May 21, 1937 Wu, 7% *4 21%. ATTORNEYS.

Patented May 9, 1939 1 UNITED STATES PATENT OFFICE Harold J. Brunk, Chicago, Ill., assignor to The C. F. Pease Company, a corporation of Delaware Original application May 21, 1937, Serial No. 144,090. Divided and this application January 7, 1939, Serial No. 249,796

2 Claims.

My invention relates to improvements in combined arc lamps and incandescent lamps, and while such equipment is adapted for many purposes it is particularly useful as a source of light in blue print machines and the like. This application is a division of my copending application 144,090, filed May 21, 1937, now Patent 2,149,505 of March '7, 1939, for Combined arc lamps and incandescent lamps.

The main object of the invention is to provide equipment converting a much larger proportion of the energy into usable light than has heretofore been possible with arc lamps.

The solenoid type of operating mechanism is preferred in arc lamps of the automatic type, wherein the separation of the carbons from each other is properly adjusted by the pull of the solenoid, which is in turn a function of the current bow across the carbons. When the carbons are separated too far, the resistance of the arc gap increases, the current flow across the gap decreases, and thus the solenoid pull is lessened and permits the carbons to move relatively closer together until the increasing current flow stops such movement.

For many reasons it has been found undesirable to pass more than eight or ten amperes through the solenoid of the average lamp of this type, and in order to increase the amount of light radiated by the arc it is necessary to pass current through the carbons by some second or additional circuit which does not include the solenoid. My joint Patent 1,992,650, issued February 26, 1935, shows a method of increasing the current through the carbons without changing the current through the solenoid, by establishing a second or shunt circuit around the solenoid after the carbons have separated and assumed proper operating position. This enables the current density across the gap, and thus the light intensity, to be varied through a wide range, while the arc lamp maintains great stability.

Such a secondary circuit, however, must absorb a voltage drop equal to that across the solenoid. That is, should the carbons and the solenoid be in series across a 220 volt supply line, either A. C. or D. C., and each have a 110 volt drop thereacross, it is necessary that the second or shunt circuit include a ballast resistance of some type substantially equivalent to the arc gap resistance in order to absorb the extra 110 volt drop when it is placed in series with the carbons across the supply line. It is always necessary to use also a ballast resistance in series with the solenoid in order to achieve arc stability.

It has heretofore been customary to use im peda-nces of one type or another for such ballast purposes, as shown in my prior patent. Such ballast resistances absorb power without giving oif light, which latter is the desired output in the case of a lamp.

The present invention comprises means for greatly increasing the light output of such devices, more particularly by providing a lamp circuit wherein all ballast resistances are replaced by auxiliary lamps when the carbons have separated sufficiently for proper operation.

Another object is to provide an arc lamp in which the resistor, which is in shunt with the solenoid but in series with the arc, is replaced by I an incandescent lamp, whereby by selecting a lamp of the proper amperage, the amount of light emitted by the arc may be very greatly increased,

by greatly increasing the flow of current through the arc, in fact such flow may be doubled.

Other features and advantages of this invention will be apparent from the following specification.

The figure of the drawing is a circuit diagram of a lamp, wherein all ballast resistances are replaced by auxiliary lamps when the carbons have separated the proper distance.

In the drawing the carbons I9 and II are movable with respect to each other and are supported in the usual manner. The upper carbon is moved by a rocker arm, not shown. This rocker arm actuates two mercury switches I2 and I3. The auxiliary lamp I4 is connected in series with the switch I2 and another auxiliary lamp I5 is connected in series with the switch I3. These lamps are incandescent lamps, as shown, the larger one being preferably one of considerable power such, for example, as one thousand watts. In addition to being connected in series with the mercury switch I2, lamp I4 is in series with the carbons I0 and II. The smaller lamp I5 may be assumed to be a six hundred watt lamp.

The circuit to the arc lamp may be assumed to be closed, in the diagram, and the solenoid I6 energized, and the two lamps I4 and I5 lighted. Said solenoid I6 actuates the upper carbon, as will be understood, and the circuit from said solenoid is through the conductor I'I, through part of the mercury contacts of the switch I3, thence through the conductor I 8 to the resistance I9 and back to the other side of the circuit. The purpose of the incandescent lamp I5 is to replace said resistance I9, when the arc has been properly drawn. Said switch I3 is so arranged that when the carbons are in contact, the circuit through the conductors ll, 58 is completed and that through conductors 2e, iii is broken, due to the tilting of said switch. That is, when the carbons are in contact or the arc is just starting, all of the current flows through the solenoid it, the conductors l'l, l8, part of the switch l3 and the ballast resistance l9. As soon as the arc has been properly started, however, the circuit through conductors H and i8 will be broken and that through conductors 2t, it will be completed so that all the current flowing through the solenoid IE will now flow through the incandescent lamp l5 rather than through the resistance !9, thus converting its energy into useful life. Simultaneously, the switch l2 will complete the circuit to the lamp !4, thus providing a shunt circuit around the solenoid, and greatly increasing the total flow of current through the arc.

By properly selecting an incandescent lamp hl of the desired amperage, the flow of current through the arc may be practically doubled, or otherwise varied.

In many uses of the arc lamp, as for example by photo engravers, the amount of work done depends on the total candle power of the light source, and it is obvious that when one or more thousand watt incandescent lamps, burning at full brilliancy, are added to the are as a light source, the total foot candles of the device are greatly increased. While the light from a gasfilled tungsten lamp is not of the best frequency to make blue prints, the addition of the light has a marked value even in such work. The incandescent lamps used to replace the resistances in such blue printing lamps should be maintained in the blue printing machine between the arc lamps, where they will help to build up the weak printing area otherwise encountered therebetween.

As pointed out in the parent application, the devices to be substituted for the resistance need not necessarily be incandescent lamps but may be any other current-consuming device or translating device. Various changes, therefore, may be made in the construction and arrangement without departing from the spirit and scope of the invention as disclosed in the appended claims.

I claim:

1. Apparatus of the character described, including: an arc lamp comprising a pair otrelatively movable carbons; a solenoid for causing said relative movement; a resistor; a series circuit including said carbons, said solenoid, and said resistor; a second lamp; switch means operated by movement of said carbons for placing said second lamp in said circuit in place of said resistor; a third lamp; and means for automatically placing said third lamp in series with said carbons and in shunt about said solenoid after said carbons have moved to proper operating separation.

2. In an arc lamp circuit having supply conductors, a resistance, a pair of carbons connected across said conductors in series with said resistance, and normally in contact when nocurrent is flowing therethrough, an actuating solenoid having a core, a shunt circuit around said solenoid, said solenoid being connected in said series circuit between said carbons and said resistance, a shunt circuit around said resistance, mechanical connections to one of said carbons whereby relative movement of said solenoid and core will separate said carbons to strike an arc, two switches, the first one being in said shunt circuit around said solenoid but in series with said carbons and the second one being in said shunt circuit around said resistance but in series with said solenoid, each of said switches being actuated by said mechanical connections, said first switch being open when said carbons are in contact, but closing as said carbons separate, said second. switch having contacts controlling two circuits and normally closing the series circuit from said solenoid to said resistance when said carbons are in contact, while holding open said shunt circuit around said resistance, and serving when actuated to another position, to open said series circuit and close said shunt circuit, a light-emitting de" vice in the shunt circuit around said resistance and a light-emitting device in the circuit in series with said carbons, whereby when said are lamp is operating, the necessary resistances in the local circuits serve as auxiliary sources of light.

HAROLD J. BRUNK. 

